Roberto Troyan was allegedly bludgeoned to death by his financial adviser. Photograph: Metropolitan Police/PA

A wealthy man was found lying in a pool of blood after being bludgeoned to death by his financial adviser, who conned him out of hundreds of thousands of pounds to fund a life of luxury, a court has heard.

David Jeffs, 36, is accused of stealing £343,000 intended for investments from under the nose of client Roberto Troyan to live the high life, Croydon crown court was told.

When Troyan's funds started to dry up, and Jeffs feared his fraud was about to be discovered, he murdered the 63-year-old during a visit to his Mayfair apartment, the prosecution claim.

Troyan, who was left a vast sum of money when his civil partner died, had been beaten over the head in his kitchen so forcefully that his skull was fractured, the jury was told. Medics attending the crime scene in central London on 8 March thought Troyan had been shot, his injuries were so severe.

Jeffs allegedly tried to cover his tracks by making bogus phone calls, including two to Troyan, disposing of his blood-stained clothes and replacing them with replicas in an attempt to dupe police.

Prosecutor Edward Brown QC said: "This defendant took advantage of a frail and vulnerable man for his own gains over a long period.

"As a result, the defendant was able to live the high life, so to speak, but all at the expense of the deceased, who when the defendant first met him was a rich man.

"He died less rich by hundreds of thousands of pounds thanks to this defendant's dishonesty, says the Crown.

"When the life to which the defendant happily had become accustomed appeared to him to be about suddenly to come to an end and that there was a real possibility that his callous acts would soon be found out, the defendant killed Mr Troyan."

Jeffs used the proceeds of his fraud to treat himself to two Lotus sports cars, one costing nearly £20,000 and the second costing £52,000, which was bought with his credit card and through the part-exchange of the first car, the prosecutor said.

The married man partied in nightclubs, spending £19,500 in one visit to the Spearmint Rhino strip club and £1,150 during a night out at celebrity nightspot Chinawhite, it is claimed.

Jeffs is said to have bought hospitality tickets to rugby, at £1,400 for a pair, and a polo event, costing £1,100 for two. He is also alleged to have visited expensive hotels and restaurants and holidayed in Mauritius, Ibiza and the US.

He is also believed to have been a drug user, with evidence of cocaine and ecstasy use found at his home, the jury heard.

Brown described Jeffs as a "devious and clever man" who exploited Troyan's inability to organise his financial affairs over the course of two years.

"The defendant had come to rely on the deceased, or rather his wealth, for his own lifestyle," Brown said.

"There were expensive sports cars, expensive restaurants, hotels, holidays, clubs, and drugs too, all of which had to be paid for.

"This was all about to come to an end and he was likely to be exposed for what he really was. The consequences were dire."

The court heard that in 2005 Troyan inherited a "significant amount" of money from the successful architect Anthony Feldman, who had become his civil partner earlier that year.

Troyan was introduced to Jeffs in 2008 and charged him with finding money-making opportunities in which to plough the inheritance, as well as helping him to manage his finances.

In June that year, Jeffs made two investments in Royal Skandia life insurance bonds on behalf of his client, one for £550,000 and the other for £650,000.

Thereafter he was allegedly given blank cheques signed by Mr Troyan, despite concerns expressed at Troyan's bank.

Between February 2010 and January 2012, he used those cheques to pay a total of £343,000 into accounts in his own name, the prosecutor said.

The defendant also tried to cash a further £80,000 during the same period but the cheques bounced, the jury heard.

Jeffs had arranged to meet Troyan as his Mount Street apartment on the afternoon of March 8 to discuss his finances, it was claimed.

The jury watched CCTV footage that showed Jeffs entering the block of flats at 2.30pm that day - half an hour before the time of the planned meeting. He was seen leaving 15 minutes later.

Shortly afterwards he called Troyan's phone and, getting no answer, left a message saying he was early but had no response at his address, and that he hoped to see him soon. He left a second, similar message just before 3pm, the court heard, saying: "I still can't get hold of you".

CCTV footage is said to show him buying 20 black bin bags and two packets of wet wipes, before he went to the service station toilets. He did not emerge for more than 10 minutes, during which time the prosecution said he swapped his clothes.

The victim had been found by his cleaner at 3.57pm. She called out his name and then searched the flat when he did not answer.

Brown told the court: "As she tried to push the kitchen door, it wouldn't open. It was then that she saw Mr Troyan's feet.

"She shouted out to him if he was alright. There was no answer of course. She screamed and ran from the flat calling for help.

"Two builders working upstairs heard her screams and came running."

When they entered the flat, they came across a bloody scene, the court heard.

The victim died of his severe head injuries, having suffered severe fractures to his skull, left cheek, jaw and eye socket. He had also inhaled blood, the court heard.